Dec

22

Centers for Disease Control, and the U.S. Department of Health and Human Services have concluded that blood lead concentrations above 10 mcg/dL are hazardous to children’s development. In a PBS news presentation on Thursday, December 20, 2007, it was announced that the recently studied imported toys contained enough lead to harm the development of young children.
Herbert L. Needleman, M.D., is a leading expert on the effects of lead poisoning on children.

NeedlemanHe is a pediatrician and child psychiatrist at the University of Pittsburgh Medical Center, and is known for groundbreaking studies on the developmental implications of lead exposure. In the 1970s, measuring lead levels in children’s teeth, Needleman provided the first evidence that even low levels of lead, lower IQ, shorten attention spans and delay language skills. Needleman conducted follow-up studies on these children and showed that their deficits persisted, resulting in learning disabilities and school failure.

Needleman designed the first forward study of lead exposure in the uterus and showed it was associated with cognitive deficits later in life. His recent research shows that boys with high levels of lead in their bones have greater odds of developing aggressive or delinquent behavior, such as bullying, vandalism and shoplifting.

Needleman’s research and advocacy was instrumental in federal regulations banning lead from gasoline and paint as well as the removal of lead from government housing. The federal Centers for Disease Control and Prevention also issued guidelines for pediatric lead poisoning diagnosis and treatment due, in part, to his research.

Needleman is the founder of the Alliance to End Childhood Lead Poisoning, now called the Alliance for Healthy Homes, a national nonprofit working to prevent and eliminate home hazards such as lead, mold, radon and pesticides.

Lead exposure causes reduced IQ, learning disabilities, developmental delays, reduced height, poorer hearing, and a host of other health problems in young children. Many of these effects are thought to be irreversible. In later years, lead-poisoned children are much more likely to drop out of school, become juvenile delinquents and engage in criminal and other anti-social behavior. As reported in the New England Journal of Medicine, researchers found that even at low levels, lead exposure in children can significantly impact IQ and even delay puberty in young girls.

At higher levels, lead can damage a child’s kidneys and central nervous system and cause anemia, coma, convulsions and even death. According to the Centers for Disease Control and Prevention (CDC), about 310,000 of the nation’s 20 million children under the age of six have blood lead levels high enough to impair their ability to think, concentrate and learn.
David Bellinger, PhD is a Professor of Neurology at Harvard Medical School/Children’s Hospital in the department of Neurology. David Bellinger focuses on two broad classes of early insults to the developing nervous system, exogenous chemical exposures, (e.g., lead, fluoride, mercury, and cocaine), and endogenous metabolic insults related to serious medical conditions (e.g., congenital heart lesions). The specific aims of the chemical exposure studies are (1) to develop new strategies for exposure assessment, (2) to define the “behavioral signature”, if any, associated with different exposure scenarios, (3) to identify factors that function as effect modifiers (i.e., that either enhance or mitigate the magnitude or presentation of toxicant-related effects), and (4) to evaluate exposure abatement interventions. The specific aims of the studies on endogenous insults related to medical conditions are to characterize the associated behavioral risks.

Superman couldn’t see through lead, but doctors and psychologists did, exposing lead’s damaging effects on children’s psychological development. Lead is everywhere-in house paint, in car exhaust, even in water pipes and food cans. As a result, lead is also in our blood and bones. In the 1970’s, experts thought that children who had less than 30 micrograms of lead per deciliter of blood (30mcg / dl) were safe from its effects. However, a research team headed by pediatrician Herbert Needleman and later joined by psychologist David Bellinger exposed how dangerous even a little lead exposure can be. Dr. Needleman and his team first tested how much lead was in the baby teeth of 2335 first and second graders with no symptoms of lead poisoning. The researchers then had the 58 children with the highest lead levels and the 100 with the lowest lead levels complete a series of tests, and had teachers rate the children’s behavior. The researchers found that the high-lead children had lower IQ’s, less verbal competence, worse speech processing, and worse attention than did the low-lead children.

Lead also affected the children’s behavior: teachers consistently judged the high-lead children to have more difficulty following directions, to be more hyperactive, and to have lower overall functioning than did the low-lead children. According to the federal guidelines at the time of this study (1979), children in both the high- and low-lead groups had relatively low levels of lead in their blood. Dr. Needleman and colleagues’ results clearly showed that the high-lead children experienced significant cognitive and behavioral problems. These researchers have also demonstrated that children from both impoverished and affluent backgrounds suffer from high lead exposure, underscoring how widespread the problem is.

Significance

Needleman’s study was among the first to raise public awareness about the effects of environmental pollutants on children’s psychological development. Prior to this study and the ensuing body of research that it inspired, environmental influences on intelligence and behavior were under-appreciated. These researchers showed that even small amounts of a common metal like lead have strong effects on children’s intelligence and personality.

This body of research also ushered in an emphasis on “behavioral toxicity,” not just “somatic toxicity.” Researchers had previously focused almost exclusively on pollutants’ relationships to diseases like cancer. Needleman’s team showed that pollutants often affect children’s behavior and cognitive functioning long before disease develops. By using these psychological measures, researchers may be able to slow, stop, or even reverse the progress of disease.